Process and apparatus for welding steam turbine diaphragms

Abstract

The welding of the body and of the ring with the distributor of a steam turbine diaphragm is carried out in four different areas holding an assembly, formed by two semi-diaphragms, in a substantially vertical position, at most tilted a few degrees off vertical, while four welding units operate simultaneously, two for each face of the assembly, providing for each assembly face to be suitably heated. Two supports are provided, one movable in respect to the other for positioning and handling of the assembly to be treated. Provision is made for vertically adjusting the assembly position with respect to a referring surface, so that the area on which each welding unit works is always on the same level, whatever the dimensions of the assembly to be welded. Provision is also made for heating and insulating both the assembly faces.

What I claim is: 
     
       1. A process for welding steam turbine diaphragms, comprising temporarily assembling two semi-diaphragms into an assembly to be welded, holding the assembly in a substantially vertical position with one of the main axes of one of said semi-diaphragms at a predetermined height, rotating said assembly at a constant speed while simultaneously carrying out welding on both opposite faces of said assembly, heating each said face continuously so as to cause substantially even heating on both said assembly faces in the areas to be welded, carrying out said welding by means of self-instructing welding torches simultaneously on two different diameters for each said face, one of said diameters being disposed between a body and a semi-distributor of the turbine diaphragm to be welded, and the other diameter being disposed between said semi-distributor and a ring of the steam turbine diaphragm to be welded. 
     
     
       2. Welding apparatus to weld together a body and a semi-distributor and a ring in each of two steam turbine semi-diaphragms assembled so as to form an assembly, said apparatus comprising a support and handling unit for said assembly, a heating and insulating group for each of two opposite faces of said assembly, a welding group comprising on each said assembly face at least one self-instructing torch positioned for welding between the body and the distributor and at least one self-instructing torch positioned for welding between said distributor and said ring, the torches on opposite faces of said assembly being opposed to each other. 
     
     
       3. Apparatus as claimed in claim 2, in which said support and handling unit comprises two workpiece supports mounted for movement toward and away from each other, one of said workpiece supports having a roller and power means to rotate the roller so as to rotate said assembly. 
     
     
       4. Welding apparatus to weld together a body and a semi-distributor and a ring in each of two steam turbine semi-diaphragms assembled so as to form an assembly, said apparatus comprising an assembly support and handling unit, a heating and insulating group for each of two opposite faces of said assembly, a welding group, at least one movable support structure for the welding and heating and insulating groups, said movable support structure having an insulation means of said insulating group, said insulation means comprising a substantially vertical wall and a cap portion arranged at the top of the wall.